package gwt.client;

import java.util.ArrayList;
import java.util.Date;

import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.i18n.client.DateTimeFormat;
import com.google.gwt.i18n.client.NumberFormat;
import com.google.gwt.user.client.Random;
import com.google.gwt.user.client.Timer;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.ui.Button;
import com.google.gwt.user.client.ui.ClickListener;
import com.google.gwt.user.client.ui.FlexTable;
import com.google.gwt.user.client.ui.HorizontalPanel;
import com.google.gwt.user.client.ui.KeyboardListenerAdapter;
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.user.client.ui.TextBox;
import com.google.gwt.user.client.ui.VerticalPanel;
import com.google.gwt.user.client.ui.Widget;

/**
 * Entry point classes define <code>onModuleLoad()</code>.
 */
public class FirstGWT implements EntryPoint {
	private static final int REFRESH_INTERVAL = 5000; // ms
	  private VerticalPanel mainPanel = new VerticalPanel();
	  private FlexTable stocksFlexTable = new FlexTable();
	  private HorizontalPanel addPanel = new HorizontalPanel();
	  private TextBox newSymbolTextBox = new TextBox();
	  private Button addStockButton = new Button("Add");
	  private Label lastUpdatedLabel = new Label();
	  private ArrayList<String> stocks = new ArrayList<String>();

	  /**
	   * Entry point method.
	   */
	  public void onModuleLoad() {
	    // Create table for stock data.
	    stocksFlexTable.setText(0, 0, "Symbol");
	    stocksFlexTable.setText(0, 1, "Price");
	    stocksFlexTable.setText(0, 2, "Change");
	    stocksFlexTable.setText(0, 3, "Remove");

	    // Add styles to elements in the stock list table.
	    stocksFlexTable.setCellPadding(5);
	    stocksFlexTable.getRowFormatter().addStyleName(0, "watchListHeader");
	    stocksFlexTable.addStyleName("watchList");
	    stocksFlexTable.getCellFormatter().addStyleName(0, 1,
	        "watchListNumericColumn");
	    stocksFlexTable.getCellFormatter().addStyleName(0, 2,
	        "watchListNumericColumn");
	    stocksFlexTable.getCellFormatter().addStyleName(0, 3,
	        "watchListRemoveColumn");

	    // Assemble Add Stock panel.
	    addPanel.add(newSymbolTextBox);
	    addPanel.add(addStockButton);
	    addPanel.addStyleName("addPanel");

	    // Assemble Main panel.
	    mainPanel.add(stocksFlexTable);
	    mainPanel.add(addPanel);
	    mainPanel.add(lastUpdatedLabel);

	    // Associate the Main panel with the HTML host page.
	    RootPanel.get("stockList").add(mainPanel);

	    // Move cursor focus to the input box.
	    newSymbolTextBox.setFocus(true);

	    // Setup timer to refresh list automatically.
	    Timer refreshTimer = new Timer() {
	      public void run() {
	        refreshWatchList();
	      }
	    };
	    refreshTimer.scheduleRepeating(REFRESH_INTERVAL);

	    // Listen for mouse events on the Add button.
	    addStockButton.addClickListener(new ClickListener() {
	      public void onClick(Widget sender) {
	        addStock();
	      }
	    });

	    // Listen for keyboard events in the input box.
	    newSymbolTextBox.addKeyboardListener(new KeyboardListenerAdapter() {
	      @Override
	      public void onKeyDown(Widget sender, char keyCode, int modifiers) {
	        if (keyCode == KEY_ENTER) {
	          addStock();
	        }
	      }
	    });

	  }

	  /**
	   * Add stock to FlexTable. Executed when the user clicks the addStockButton or
	   * presses enter in the newSymbolTextBox.
	   */
	  private void addStock() {
	    final String symbol = newSymbolTextBox.getText().toUpperCase().trim();
	    newSymbolTextBox.setFocus(true);

	    // Stock code must be between 1 and 10 chars that are numbers, letters, or
	    // dots.
	    if (!symbol.matches("^[0-9a-zA-Z\\.]{1,10}$")) {
	      Window.alert("'" + symbol + "' is not a valid symbol.");
	      newSymbolTextBox.selectAll();
	      return;
	    }

	    newSymbolTextBox.setText("");

	    // Don't add the stock if it's already in the table.
	    if (stocks.contains(symbol))
	      return;

	    // Add the stock to the table.
	    int row = stocksFlexTable.getRowCount();
	    stocks.add(symbol);
	    stocksFlexTable.setText(row, 0, symbol);
	    stocksFlexTable.setWidget(row, 2, new Label());
	    stocksFlexTable.getCellFormatter().addStyleName(row, 1,
	        "watchListNumericColumn");
	    stocksFlexTable.getCellFormatter().addStyleName(row, 2,
	        "watchListNumericColumn");
	    stocksFlexTable.getCellFormatter().addStyleName(row, 3,
	        "watchListRemoveColumn");

	    // Create the Remove button.
	    Button removeStockButton = new Button("x");
	    removeStockButton.addStyleDependentName("remove");
	    removeStockButton.addClickListener(new ClickListener() {
	      public void onClick(Widget sender) {
	        int removedIndex = stocks.indexOf(symbol);
	        stocks.remove(removedIndex);
	        stocksFlexTable.removeRow(removedIndex + 1);
	      }
	    });
	    stocksFlexTable.setWidget(row, 3, removeStockButton);

	    // Get the stock price.
	    refreshWatchList();
	  }

	  /**
	   * Generate random stock prices.
	   */
	  private void refreshWatchList() {
	    final double MAX_PRICE = 100.0; // $100.00
	    final double MAX_PRICE_CHANGE = 0.02; // +/- 2%

	    StockPrice[] prices = new StockPrice[stocks.size()];
	    for (int i = 0; i < stocks.size(); i++) {
	      double price = Random.nextDouble() * MAX_PRICE;
	      double change = price * MAX_PRICE_CHANGE
	          * (Random.nextDouble() * 2.0 - 1.0);

	      prices[i] = new StockPrice((String) stocks.get(i), price, change);
	    }

	    updateTable(prices);
	  }

	  /**
	   * Update the Price and Change fields all the rows in the stock table.
	   * 
	   * @param prices Stock data for all rows.
	   */
	  private void updateTable(StockPrice[] prices) {
	    for (int i = 0; i < prices.length; i++) {
	      updateTable(prices[i]);
	    }

	    // Display timestamp showing last refresh.
	    lastUpdatedLabel.setText("Last update : "
	        + DateTimeFormat.getMediumDateTimeFormat().format(new Date()));

	  }

	  /**
	   * Update a single row in the stock table.
	   * 
	   * @param price Stock data for a single row.
	   */
	  private void updateTable(StockPrice price) {
	    // Make sure the stock is still in the stock table.
	    if (!stocks.contains(price.getSymbol())) {
	      return;
	    }

	    int row = stocks.indexOf(price.getSymbol()) + 1;

	    // Format the data in the Price and Change fields.
	    String priceText = NumberFormat.getFormat("#,##0.00").format(
	        price.getPrice());
	    NumberFormat changeFormat = NumberFormat.getFormat("+#,##0.00;-#,##0.00");
	    String changeText = changeFormat.format(price.getChange());
	    String changePercentText = changeFormat.format(price.getChangePercent());

	    // Populate the Price and Change fields with new data.
	    stocksFlexTable.setText(row, 1, priceText);
	    Label changeWidget = (Label) stocksFlexTable.getWidget(row, 2);
	    changeWidget.setText(changeText + " (" + changePercentText + "%)");

	    // Change the color of text in the Change field based on its value.
	    String changeStyleName = "noChange";
	    if (price.getChangePercent() < -0.1f) {
	      changeStyleName = "negativeChange";
	    } else if (price.getChangePercent() > 0.1f) {
	      changeStyleName = "positiveChange";
	    }

	    changeWidget.setStyleName(changeStyleName);

	  }
}
